275 lines
8.1 KiB
Rust
275 lines
8.1 KiB
Rust
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use core::fmt;
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use byteorder::{ByteOrder, NetworkEndian};
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use Error;
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use super::ip::rfc1071_checksum;
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enum_with_unknown! {
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/// Internet protocol control message type.
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pub doc enum Type(u8) {
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/// Echo reply
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EchoReply = 0,
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/// Destination unreachable
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DstUnreachable = 1,
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/// Message redirect
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Redirect = 5,
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/// Echo request
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EchoRequest = 8,
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/// Router advertisement
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RouterAdvert = 9,
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/// Router solicitation
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RouterSolicit = 10,
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/// Time exceeded
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TimeExceeded = 11,
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/// Parameter problem
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ParamProblem = 12,
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/// Timestamp
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Timestamp = 13,
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/// Timestamp reply
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TimestampReply = 14
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}
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}
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enum_with_unknown! {
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/// Internet protocol control message subtype for type "Destination Unreachable".
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pub doc enum DstUnreachable(u8) {
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/// Destination network unreachable
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NetUnreachable = 0,
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/// Destination host unreachable
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HostUnreachable = 1,
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/// Destination protocol unreachable
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ProtoUnreachable = 2,
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/// Destination port unreachable
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PortUnreachable = 3,
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/// Fragmentation required, and DF flag set
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FragRequired = 4,
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/// Source route failed
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SrcRouteFailed = 5,
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/// Destination network unknown
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DstNetUnknown = 6,
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/// Destination host unknown
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DstHostUnknown = 7,
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/// Source host isolated
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SrcHostIsolated = 8,
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/// Network administratively prohibited
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NetProhibited = 9,
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/// Host administratively prohibited
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HostProhibited = 10,
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/// Network unreachable for ToS
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NetUnreachToS = 11,
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/// Host unreachable for ToS
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HostUnreachToS = 12,
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/// Communication administratively prohibited
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CommProhibited = 13,
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/// Host precedence violation
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HostPrecedViol = 14,
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/// Precedence cutoff in effect
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PrecedCutoff = 15
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}
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}
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enum_with_unknown! {
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/// Internet protocol control message subtype for type "Redirect Message".
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pub doc enum Redirect(u8) {
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/// Redirect Datagram for the Network
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Net = 0,
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/// Redirect Datagram for the Host
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Host = 1,
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/// Redirect Datagram for the ToS & network
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NetToS = 2,
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/// Redirect Datagram for the ToS & host
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HostToS = 3
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}
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}
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enum_with_unknown! {
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/// Internet protocol control message subtype for type "Time Exceeded".
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pub doc enum TimeExceeded(u8) {
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/// TTL expired in transit
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TtlExpired = 0,
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/// Fragment reassembly time exceeded
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FragExpired = 1
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}
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}
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enum_with_unknown! {
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/// Internet protocol control message subtype for type "Parameter Problem".
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pub doc enum ParamProblem(u8) {
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/// Pointer indicates the error
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AtPointer = 0,
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/// Missing a required option
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MissingOption = 1,
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/// Bad length
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BadLength = 2
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}
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}
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/// A read/write wrapper around an Internet Control Message Protocol version 4 packet buffer.
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#[derive(Debug)]
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pub struct Packet<T: AsRef<[u8]>> {
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buffer: T
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}
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mod field {
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#![allow(non_snake_case)]
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use wire::field::*;
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pub const TYPE: usize = 0;
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pub const CODE: usize = 1;
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pub const CHECKSUM: Field = 2..4;
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pub const ECHO_IDENT: Field = 4..6;
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pub const ECHO_SEQNO: Field = 6..8;
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}
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impl<T: AsRef<[u8]>> Packet<T> {
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/// Wrap a buffer with an ICMPv4 packet. Returns an error if the buffer
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/// is too small to contain one.
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pub fn new(buffer: T) -> Result<Packet<T>, Error> {
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let len = buffer.as_ref().len();
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if len < field::CHECKSUM.end {
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Err(Error::Truncated)
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} else {
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let packet = Packet { buffer: buffer };
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if len < packet.header_len() {
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Err(Error::Truncated)
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} else {
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Ok(packet)
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}
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}
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}
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/// Consumes the packet, returning the underlying buffer.
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pub fn into_inner(self) -> T {
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self.buffer
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}
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/// Return the message type field.
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#[inline(always)]
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pub fn msg_type(&self) -> Type {
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let data = self.buffer.as_ref();
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Type::from(data[field::TYPE])
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}
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/// Return the message code field.
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#[inline(always)]
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pub fn msg_code(&self) -> u8 {
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let data = self.buffer.as_ref();
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data[field::CODE]
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}
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/// Return the checksum field.
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#[inline(always)]
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pub fn checksum(&self) -> u16 {
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let data = self.buffer.as_ref();
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NetworkEndian::read_u16(&data[field::CHECKSUM])
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}
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/// Return the identifier field (for echo request and reply packets).
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///
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/// # Panics
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/// This function may panic if this packet is not an echo request or reply packet.
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#[inline(always)]
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pub fn echo_ident(&self) -> u16 {
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let data = self.buffer.as_ref();
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NetworkEndian::read_u16(&data[field::ECHO_IDENT])
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}
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/// Return the sequence number field (for echo request and reply packets).
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///
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/// # Panics
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/// This function may panic if this packet is not an echo request or reply packet.
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#[inline(always)]
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pub fn echo_seq_no(&self) -> u16 {
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let data = self.buffer.as_ref();
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NetworkEndian::read_u16(&data[field::ECHO_SEQNO])
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}
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/// Return the header length.
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/// The result depends on the value of the message type field.
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pub fn header_len(&self) -> usize {
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match self.msg_type() {
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Type::EchoRequest => field::ECHO_SEQNO.end,
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Type::EchoReply => field::ECHO_SEQNO.end,
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_ => field::CHECKSUM.end // make a conservative assumption
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}
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}
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/// Return a pointer to the type-specific data.
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#[inline(always)]
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pub fn data(&self) -> &[u8] {
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let data = self.buffer.as_ref();
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&data[self.header_len()..]
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}
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/// Validate the header checksum.
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pub fn verify_checksum(&self) -> bool {
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let checksum = {
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let data = self.buffer.as_ref();
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rfc1071_checksum(field::CHECKSUM.start, &data[..self.header_len()])
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};
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self.checksum() == checksum
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}
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}
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impl<T: AsRef<[u8]> + AsMut<[u8]>> Packet<T> {
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/// Set the message type field.
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#[inline(always)]
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pub fn set_msg_type(&mut self, value: Type) {
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let mut data = self.buffer.as_mut();
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data[field::TYPE] = value.into()
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}
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/// Set the message code field.
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#[inline(always)]
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pub fn set_msg_code(&mut self, value: u8) {
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let mut data = self.buffer.as_mut();
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data[field::CODE] = value
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}
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/// Set the checksum field.
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#[inline(always)]
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pub fn set_checksum(&mut self, value: u16) {
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let mut data = self.buffer.as_mut();
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NetworkEndian::write_u16(&mut data[field::CHECKSUM], value)
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}
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/// Set the identifier field (for echo request and reply packets).
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///
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/// # Panics
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/// This function may panic if this packet is not an echo request or reply packet.
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#[inline(always)]
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pub fn set_echo_ident(&mut self, value: u16) {
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let mut data = self.buffer.as_mut();
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NetworkEndian::write_u16(&mut data[field::ECHO_IDENT], value)
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}
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/// Set the sequence number field (for echo request and reply packets).
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///
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/// # Panics
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/// This function may panic if this packet is not an echo request or reply packet.
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#[inline(always)]
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pub fn set_echo_seq_no(&mut self, value: u16) {
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let mut data = self.buffer.as_mut();
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NetworkEndian::write_u16(&mut data[field::ECHO_SEQNO], value)
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}
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/// Return a mutable pointer to the type-specific data.
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#[inline(always)]
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pub fn data_mut(&mut self) -> &mut [u8] {
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let range = self.header_len()..;
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let mut data = self.buffer.as_mut();
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&mut data[range]
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}
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/// Compute and fill in the header checksum.
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pub fn fill_checksum(&mut self) {
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let checksum = {
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let data = self.buffer.as_ref();
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rfc1071_checksum(field::CHECKSUM.start, &data[..self.header_len()])
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};
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self.set_checksum(checksum)
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}
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}
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